1. Field of the Invention
The present invention relates to novel heterocyclic compounds and more particularly to eburnamonine oxime derivatives, salts thereof, process for the manufacture the same as well as pharmaceutical agents containing the compound as an effective component. The compounds of the invention are represented by the general formula ##STR3##
wherein R is alkyl or a group of ##STR4## R.sup.1 and R.sup.2 are same or different and respectively hydrogen, alkyl having 1 to 4 carbon atoms, aryl or aralkyl group, or R.sup.1 is together with R.sup.2 and the neighbouring nitrogen atom a non-substituted or substituted heterocyclic ring, and n is an integer of 2 or 3.
Each of such compounds exhibits good or favorable pharmacological activities of cerebral vasodilating and metabolic activating actions and thus it is useful as an effective component for pharmaceutical agent.
2. Prior Arts
It has been known that Periwinkle (Vinca minor L. Apocyaceae) contains therein various alkaloids of vincamine, vincine, vincaminine, vincinine and the like. Among them, the vincamine has been employed as an ameliorant for curing cerebral circulatory disturbances. However, the vincamine has a disadvantage of that its effective action in a relatively short time period.
In order to overcome the disadvantage in at least some measure, various vincamine derivatives, for instance the followings have been proposed. ##STR5##
Such synthetic vincamine derivatives have clinically been employed as a cerebral vasodilating or cerebral metabolism improving agent but have disadvantages in that pharmacological actions thereof are somewhat or remarkably low and a sustenance of the actions is not sufficient.